Division of Compensation Analysis and 

Support

Program Evaluation Report

Document Number: DCAS-PER-037

Effective Date: 7/17/2012

Revision No. 0

Ames Laboratory TBD Revision Page 1 of 3

Author: Signature on file Date: 07/17/2012 

 Dave Allen, HP Team Leader

Approval: Signature on file Date: 07/17/2012 

 J.W. Neton, Associate Director for Science

Supersedes: None

RECORD OF ISSUE/REVISIONS

ISSUE 

AUTHORIZATION 

DATE

7/17/2012

EFFECTIVE 

DATE

7/17/2012

REV. NO. 

0

DESCRIPTION

New document to determine which 

previously completed claims require 

evaluation for the affect of revising the 

Ames Laboratory TBD.

1.0 Description

Revision 3 of the Ames Laboratory Technical Basis Document (ORAU-TKBS-0055) was 

issued on 1/3/2012. The previous version (revision 2) was issued on 1/14/2011. 

Revision 1 was issued 12/18/2009 and revision 0 PC-1 was issued 8/20/2008. This PER 

considered the changes that were made between the current revision (revision 3) and all 

previous versions of the TBD. 

2.0 Issue Evaluation

Several changes in these revisions resulted in either an increase or a decrease in assigned 

dose. Some doses decrease in one revision and then increase in a subsequent revision. In 

order to evaluate the effect on previous dose reconstruction if they were to be 

recalculated today, the changes that resulted in an increase in dose in any revision and 

would still be assigned in revision 3 are considered. Those changes are listed below.

Revision 1 of the TBD included an increase in the uranium intakes for researchers in the 

chemistry building from August 1942 through December of 1953. Revision 2 and 3 also 

included these intakes which are identical to revision 1.

Revision 2 of the TBD included an increase in uranium intakes for all employees in the 

chemistry building between January 1954 and May 1976. The higher intakes remain the 

same in revision 3. 

External dose for unmonitored workers before 1946 increased in revision 1 for some job 

categories and locations. These values remained the same in revision 2 but then increase 

again in revision 3. 
Division of Compensation Analysis and 

Support

Program Evaluation Plan

Document Number: DCAS-PER-037

Effective Date: 7/17/2012 Revision No. 0 Page 2 of 3

External dose for unmonitored workers between 1946 and 1953 decreased for all job 

categories and locations in revision 1. The values remained the same in revision 2 but 

increase in revision 3. The revision 3 increase was still below the revision 0 values with 

the exception of extremity dose in annex 2.

3.0 Plan for Resolution or Corrective Action

Based on the issues described above, two populations of claims potentially affected by 

these revisions were determined. The first population was based on the following 

criteria:

1. Probability of Causation (PC) less than 50%

2. Most recent version of the dose reconstruction approved by DCAS on or prior to 

January 3, 2012 (issue date of the current TBD revision).

3. Employed at the Ames Laboratory prior to 1954.

These criteria identified total of 19 claims. Two of these claims met the criteria for 

inclusion in the SEC and had no additional non-listed cancers. The assigned internal and 

external dose for the remaining 17 claims was reviewed and compared to the assigned 

doses in revision 3 of the TBD. Seven of those were assigned doses at least as high as 

revision 3. The remaining 10 were evaluated further as discussed below. 

The second population of potentially affected claims was developed from the following 

criteria:

1. Probability of Causation (PC) less than 50%

2. Most recent version of the dose reconstruction approved by DCAS on or prior to 

January 3, 2012 (issue date of the current TBD revision).

3. Employed at the Ames Laboratory between January 1st 1954 and June 1976.

These criteria identified total of 61 claims. Sixteen of these claims met the criteria for 

inclusion in the SEC and had no additional non-listed cancers. The remaining claims 

were reviewed to determine if chemistry building intakes had been assigned in the 

previous dose reconstruction. That review determined that six claims were assigned 

chemistry building intakes based on a previous version of the TBD. Those six claims 

were evaluated further as discussed below. 

3.1 Determination of claims which will not change due to TBD revision. 

For the sixteen claims requiring further evaluation, dose was recalculated using all 

current dose reconstruction methods including the current version of the TBD. From that 
Division of Compensation Analysis and 

Support

Program Evaluation Plan

Document Number: DCAS-PER-037

Effective Date: 7/17/2012 Revision No. 0 Page 3 of 3

recalculated dose, a new probability of causation was determined. The probability of 

causation remained below 45% for 13 of the 16 claims. Two were just above 45% but 

below 50%, therefore, IREP was run 30 times using 10,000 iteration to determine the 

probability of causation more precisely. This resulted in little change with each resulting 

probability of causation between 45% and 46%. The final claim resulted in a probability 

of causation greater than 50%. NIOSH will notify DOL of these results and request a 

return of the one case that would now be greater than 50%.